Subdivision of the Silurian Period | ||||||||
−444 — – −442 — – −440 — – −438 — – −436 — – −434 — – −432 — – −430 — – −428 — – −426 — – −424 — – −422 — – −420 — – |
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Subdivision of the Silurian according to the ICS, as of 2024.3 Vertical axis scale: Millions of years ago | ||||||||
The Mulde event was an anoxic event,4 and marked the second of three1 relatively minor mass extinctions (the Ireviken, Mulde, and Lau events) during the Silurian period. It coincided with a global drop in sea level, and is closely followed by an excursion in geochemical isotopes. Its onset is synchronous with the deposition of the Fröjel Formation in Gotland.4 Perceived extinction in the conodont fauna, however, likely represent a change in the depositional environment of sedimentary sequences rather than a genuine biological extinction.5
Higher resolution δ13C isotope analysis identifies differences in the organic and carbonate carbon isotope curves (Δ13C), allowing the inference of a sustained drop in CO2 levels coincident with the extinction once sedimentological data are taken into account.6
References
References
- Jeppsson, Lennart; Calner, Mikael (June 2002). "The Silurian Mulde Event and a scenario for secundo—secundo events". Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 93 (2): 135–154. doi:10.1017/S0263593300000377. eISSN 1755-6929. ISSN 1755-6910. LCCN 2007237265. OCLC 184982680. S2CID 129308139.
- Munnecke, Axel; Samtleben, Christian; Bickert, Torsten (June 5, 2003). "The Ireviken Event in the lower Silurian of Gotland, Sweden-relation to similar Palaeozoic and Proterozoic events". Palaeogeography, Palaeoclimatology, Palaeoecology. 195 (1–2): 99–124. Bibcode:2003PPP...195...99M. doi:10.1016/S0031-0182(03)00304-3. eISSN 1872-616X. ISSN 0031-0182. LCCN 65009956. OCLC 1761774. S2CID 129353726. Retrieved December 12, 2025.
- "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. December 2024. Retrieved October 23, 2025.
- Samtleben, C.; Munnecke, A.; Bickert, T. (2000). "Development of facies and C/O-isotopes in transects through the Ludlow of Gotland: Evidence for global and local influences on a shallow-marine environment". Facies. 43 (1): 1–38. Bibcode:2000Faci...43....1S. doi:10.1007/BF02536983. S2CID 130640332.
- Jarochowska, Emilia; Ray, David C; Röstel, Philipp; Worton, Graham; Munnecke, Axel (2017). "Harnessing stratigraphic bias at the section scale: Conodont diversity in the Homerian (Silurian) of the Midland Platform, England". Palaeontology. 61: 57–76. doi:10.1111/pala.12326. S2CID 135200300.
- Biebesheimer, Ellie J.; Cramer, Bradley D.; Calner, Mikael; Barnett, Bruce A.; Oborny, Stephan C.; Bancroft, Alyssa M. (2021). "Asynchronous δ13Ccarb and δ13Corg records during the onset of the Mulde (Silurian) positive carbon isotope excursion from the Altajme core, Gotland, Sweden". Chemical Geology. 576 120256. Bibcode:2021ChGeo.57620256B. doi:10.1016/j.chemgeo.2021.120256. ISSN 0009-2541. S2CID 234817512.